Get yourself a Wyeth-Scott "More Power Puller". It is a 3-ton, 6000#, vertical lift hand winch that will pull 12,000# equal to the slope that electric winches are rated. If you can find an anchor point it would most likely get you out of a ditch.
Carry one with you. You need 2 steel fence posts cut off about 3' above the fin, a big hammer, and some strong non-stretchy rope.
Drive a post where you need an anchor, leaning a bit away from the truck. Drive it until the fin is totally buried, deeper in soft soil or sand. Drive the 2d one about 3 or 4' behind it the same way. Tie the rope to the top of the front post and take a few wraps to the bottom of the 2d post. Welding a couple cross pieces to the posts will help keep the rope from slipping. Tie your winch rope to the bottom of the 1st post.
If you anticipate sandy soil, add a 3d post.
